[SOLVED] Netctl routing with two interfaces/profiles

o1iver · 2014-07-18 09:55:45

Hi,

I am having a problem with IP traffic routing when using two network interfaces.

I have two network interfaces configured (this is on a set of VirtualBox VMs):

ost@lithium ~> ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
2: enp0s3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
link/ether 08:00:27:a6:95:56 brd ff:ff:ff:ff:ff:ff
inet 10.0.2.5/24 brd 10.0.2.255 scope global enp0s3
valid_lft forever preferred_lft forever
3: enp0s8: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
link/ether 08:00:27:8c:1c:3e brd ff:ff:ff:ff:ff:ff
inet 10.1.1.11/24 brd 10.1.1.255 scope global enp0s8
valid_lft forever preferred_lft forever

enp0s3 is connected to a VirtualBox NAT network where 10.0.2.* are provided via DHCP
enp0s8 is connected to a VirtualBox host-only network without DHCP.

I am using netctl for network configurations. I have a profile for each interface:

enp0s3

ost@lithium ~> cat /etc/netctl/network-profile_vb-nat
Description='Network Profile: VirtualBox NAT using dhcp.'
Interface=enp0s3
Connection=ethernet
IP=dhcp

enp0s8

ost@lithium ~> cat /etc/netctl/network-profile_vb-host-only_static
Description='Network Profile: VirtualBox Host-Only using static IP 10.1.1.11.'
Interface=enp0s8
Connection=ethernet
IP=static
Address=('10.1.1.11/24')
Gateway='10.1.1.1'
DNS=('10.1.1.1')

No profiles are loaded on boot. I am starting everything manually.

If I use only the enp0s8 profile, i.e.

ost@lithium ~> sudo netctl start network-profile_vb-host-only_static

I am able to ping/ssh any machines in the 10.1.1.* network (i.e. the VirtualBox host-only network).

If I use only the enp0s3 profile, i.e.

ost@lithium ~> sudo netctl start network-profile_vb-nat

I am able to connect to my host machine and to the network thereafter (incl. the internet).

Now my problem occurs when I try to use both profiles at the same time, i.e.:

ost@lithium ~> sudo netctl start network-profile_vb-host-only_static
ost@lithium ~> sudo netctl start network-profile_vb-nat

In that situation I am still able to connect to machines with 10.1.1.* addresses (i.e. in the host-only network), but I am no longer able to access the internet through the host's NAT.

Looking at the routes I get the following:

ost@lithium ~> ip route
default via 10.1.1.1 dev enp0s8
default via 10.0.2.1 dev enp0s3 metric 202
10.0.2.0/24 dev enp0s3 proto kernel scope link src 10.0.2.5 metric 202
10.1.1.0/24 dev enp0s8 proto kernel scope link src 10.1.1.11
ost@lithium ~> ping google.com
^Cfish: Job 1, “ping google.com” terminated by signal SIGINT (Quit request from job control (^C)) #TIMEOUT

I can remove a route using the following command to restore access to the internet:

ost@lithium ~> sudo ip route delete default via 10.1.1.1 dev enp0s8
ost@lithium ~> ip route
default via 10.0.2.1 dev enp0s3 metric 202
10.0.2.0/24 dev enp0s3 proto kernel scope link src 10.0.2.5 metric 202
10.1.1.0/24 dev enp0s8 proto kernel scope link src 10.1.1.11
ost@lithium ~> ping google.com
PING google.com (173.194.44.65) 56(84) bytes of data.
64 bytes from ham02s14-in-f1.1e100.net (173.194.44.65): icmp_seq=1 ttl=55 time=8.75 ms
^C
--- google.com ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 8.756/8.756/8.756/0.000 ms

Now I want to avoid deleting the route manually using ip route delete and am trying to understand how I need to change my netctl profiles to make this work automatically (i.e. simply by starting/stopping the profiles).

I would be grateful for any guidance!
Thanks

Last edited by o1iver (2014-07-21 13:10:48)

andy123 · 2014-07-18 13:16:58

Hey,

at first glance I'd say remove the "Gateway='10.1.1.1'" line from /etc/netctl/network-profile_vb-host-only_static

o1iver · 2014-07-21 07:36:42

That worked perfectly. Thank you very much!

karol · 2014-07-21 10:03:42

Please remember to mark the thread as solved https://bbs.archlinux.org/viewtopic.php?id=130309

Arch Linux

#1 2014-07-18 09:55:45

[SOLVED] Netctl routing with two interfaces/profiles

#2 2014-07-18 13:16:58

Re: [SOLVED] Netctl routing with two interfaces/profiles

#3 2014-07-21 07:36:42

Re: [SOLVED] Netctl routing with two interfaces/profiles

#4 2014-07-21 10:03:42

Re: [SOLVED] Netctl routing with two interfaces/profiles

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